Mold for manufacture of rubber thread-loops.



T. SLOPEH.

MOLD FOR MANUFACTURE 0F RUBBER THREAD LOUPS.

APPLICA'IION FILED OCT. 9, 1915.

` 1,198,874. mqmasvpl.10,1916.

2 SHEUSfYSHEET l.

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MOLD FUR MANUFACTURE 0F RUBBH THREAD LOOPS.

APPLICATION m50 001.9, wm.

1 ,198,8'74. Patented Svpt. l2), 19113.

2 SHEETS-SHEET 2.

WL'( asses WWW ` To all whom it may "concern:

UNITED STATES PATENT oEEIoE.

THOMAS SLOPEB, OF DEVIZES, ENGLAND.

MOLD FOR MANUFACTURE 0F RUBBER THREAD-LOOPS.

specification Leners patent Lpatented Sept, 19y 1916,

l AApplication tiled October 9, 1915. Serial No. 55,104,

.Be it known that I, THOMAS SLoPEn, a subject of the King of England, residing at Devizes, in Wiltshire, England, have invented certain new and useful Improvements in Molds for the Manufacture of Rubber Thread-Loops, of whichvthe following is a specification.

This invention is for a mold for use in the manufacture of strain insulators These insulators as used for acrials have heretofore been built up by winding rubbered thread (usually. in the form of cord) on 'a former in'an elongated loop, the threads being pressed together by hand -sothat they adhered one to another, removing the loop' thus built' up from the former, and collapsing the sides together without closing.

the ends so that eyes were formed at the ends to receive thimbles or other fastening means. The insulator thus built up was then lashed at its ends and nally coated with rubber and vulcanized. It has been'found that in making up suoli insulators, the threads although laid parallel to each other when winding them on the former, often got displaced 4during the further-steps in the manufacture, so that the resulting insulator was weakened in that all the threads did not take their proper proportion of the strain.

The present invention provides a mold` whereby the threads may be pressed together Without being displaced out of their rop'er relative'positions, and which may Ee used in the process set forth in my concurrent United States pateni.. application Serial No. 18324, filed March 3i, 1915.

In the accompanying drawingszmFigure l is a transverse section through a mold constructed according to this invention; Fig. 2 shows the same section as Fig. 1 but with the parts in a different position; Fig. 3 shows a section similar to F ig.' 1, but in a different plane, with the parts in yet another position and a further element added, and

Fig. 4 is a section on the line 8-8 of Fig. 2..v

The same letters indicate the same parts throughout the drawings. l

In building up the insulators, rubbered threads A, such as are well-known from their 1x1-:e in the manufacture of Palmer cord tires, are first wound upon a former B, Figs. L-4, which former in shape resembles a `at C2.

rectangular bar having rounded ends, and the'thread is so wound upon it as to constitute when removed from the former an elongated loop, as can be seen by reference to Figs. 1-4. The threads are laid parallel to each other and in laying them as even a tension as possible is maintained throughout.A The rubbered thread, as is known, is tacky, so that when laid together the coils will adhere to some extent to one another, but it has been found that pressing 'them together'by hand does not cause them to adhere to one another sufficiently to prevent derangement during their removal from the former or during their subsequent treatment. To cause them to adhere firmly to one lanother', the mold shown in Figs. 1-4 is therefore employed. This-mold comprises a base-die C and a. cooperating die D. The base-die is provided with a through slot which at C* is made to lit the ,former B but below this the slot is enlarged as shown The upper face of the die C is recessed about the slot at C, the 4bottom part of this recess being made of Such size and shape as to correspond to the size and shape the lower halfv of the loop of thread A is required to take when compressed by the dies While still on the former,

The upper die D has a tongue Dl which enters the rece Ca and has its lower face D2 shaped to correspond to the size and form the upper half of the loop of thread is required to take. The die D is conveniently guided in the die C by pins D3 and may connected to the movable member of a press,90

or it may be operated merely by striking it.'

The thread A is conveniently wound on the middle portion of the formeimfB so that the.former projects both above and below theloop as shown in Fig. 1. 1't follows therefore that as the die D is forced home, it first drives the former lB partially through the loop and then com resses the thead so that the parts finally take the position shown in Fig. 2.

The die D is provided with two or more perforations D which extend from its upper face through the tongue D1 so that a driver comprising a' lplate E and having two or more pins E? w ich register with and slide through the perforations D* can be employed to discharge the former B from the loop.

whereas if the former is thrust out of--thev loop by forcing the driver E downward until the pins El drive the former .right through the loop into the enlargement C2 of theithrough-way slot in the die C, the threads are held meanwhile by the dies so that they cannot be displaced relatively to one another.

In Fig. 3, the driver is shown as having been advanced and the former B is shown lying in the enlargement C2 of the slot in the die C. This enlargement is conveniently made of sufficient depth toaccommodate the former so that the dies may stand upon a iiat surface if desired, while the former"7 is being thrust out, and the former will then be found quite loose in the bottom of the die C. The driver E is conveniently Y operated in the same press as is employed for consolidatingl the core.

The loop of thread A after compression in the lmanner above described in the press tool is removed therefrom and 'formed into a strain insulator in the manner described in my concurrent United States application hereinabove referred to.

What I claim as my invention and desire to secure by Letters Patent is In a mold for shaping rubber thread loops, the combination of, a diev slotted to receive the former whereon the loop is placed and recessed about the slot in one face to receive the loop on the former said slot being made to fit the lformer at the recess and the recess being shaped to correspond to the form the exterior of one half of L the loop is to take while on the former, a coperating die having a face which registers with the recess in the first-mentioned die, said face being shaped to the form the exterior of the second half of the loop is ret quired to take while on the formen, and

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS SLOPER. Witnesses:

HAROLD PARsoNs, ROBERT CANTWELL. 

